. >> reporter: it could also pump lots of money into local economies. >> the san francisco controller's office came out with a report last year that said $4.2 billion was pumped into the san francisco economy from the nightlife directly. >> it would probably be bad for, like, police enforcement, those having to do their job more. >> there's a school of thought goes, wait a minute, there's nothing good that happens after 2:00. [ laughter ] >> i don't know. a lot of good things happen after 2:00! [ laughter ] >> reporter: just so it's clear, the law as it stands now allows some places to stay open until 4:00 am. they just have to cut off alcohol at 2:00 am. back here, they have to cut it off at 2:00 am, and everybody has to go home at 1:00 am. >> so are people worried that by keeping the bars open longer, it may lead to more problems like fighting and even duis? >> reporter: that is a good question. and the senator said they looked at the scientific data in other cities that do this, las vegas, and new orleans, and there are no facts to support what you might suppose, that there is an upt